The Field of the Invention
This application relates generally to cutting tools and their methods of use. In particular, this application relates to diamond-impregnated cutting tools that may contain fibers.
Discussion of the Relevant Art
Cutting tools can be impregnated with diamonds so that they can be used to grind, polish, or otherwise cut a variety of materials that normal cutting tools cannot. The part of these tools that performs the cutting action (or the cutting portion of the tool) is generally formed of a matrix that contains a powdered metal or a hard particulate material, such as tungsten carbide. This material is sometimes infiltrated with a binder, such as a copper alloy. Finally, the cutting portion of these tools is impregnated with diamond crystals or some other form of abrasive cutting media. As the tool grinds and cuts the desired materials, the cutting portion of the tool erodes and exposes new layers of the diamond crystal (or other cutting media) so that a sharp surface is always available for the cutting process. Any diamond-impregnated cutting tool may continue to cut efficiently until the diamond impregnated portion of the tool is completely consumed. At that point, the tool becomes dull and must be replaced with another one.
In some cases, diamond-impregnated cutting tools may be expensive and their replacement may be time consuming, costly, as well as dangerous. For example, the replacement of a diamond-impregnated core sampling drill bit requires removing (or tripping out) the entire drill string out of the hole that has been drilled (the borehole). Each section of the drill rod must be sequentially removed from the borehole. Once the drill bit is replaced, the entire drill string must be assembled section by section and then tripped back into the borehole. Depending on the depth of the hole and the characteristics of the materials being drilled, this process may need to be repeated multiple times for a single borehole.
As well, conventional diamond-impregnated cutting tools often have several characteristics that can add to the consumption rate of the cutting portion and, therefore, increase the operating costs associated with those cutting tools. First, the binder materials in the tools may be relatively soft in comparison to the cutting media. Accordingly, the cutting portion may erode and allow diamonds or other abrasive cutting materials to slough off prematurely. Second, the erosion rate of the cutting portion can be increased by insufficient lubrication to and around the cutting face of the tool, or the interface between the cutting portion of the tool and the material being cut. Third, conventional impregnated cutting tools may also be too wear resistant to expose and renew layers of the cutting portion.